(a) Field of the Invention
The present invention relates to a liquid crystal display.
(b) Description of the Related Art
A liquid crystal display (LCD) is one of the most widely used flat panel displays. An LCD includes two panels provided with field-generating electrodes such as pixel electrodes and a common electrode and a liquid crystal (LC) layer interposed therebetween. The LCD displays images by applying voltages to the field-generating electrodes to generate an electric field in the LC layer, which determines orientations of LC molecules in the LC layer to adjust polarization of incident light.
Among the LCDs, a vertical alignment (VA) mode LCD, which aligns LC molecules such that the long axes of the LC molecules are perpendicular to the panels in absence of electric field, is spotlighted because of its high contrast ratio and wide viewing angle.
The wide viewing angle of the VA mode LCD can be realized by cutouts in the field-generating electrodes and protrusions on the field-generating electrodes. Since the cutouts and the protrusions can determine the tilt directions of the LC molecules, the tilt directions can be distributed into several directions by using the cutouts and the protrusions such that the viewing angle is widened. In particular, a patterned VA (PVA) mode LCD employing the cutouts is preferred as a substitute of an in-plane switching (IPS) mode LCD.
The PVA mode LCD has a fast response time compared with a twisted nematic (TN) mode LCD since the motions of the LC molecules only include elastic splay or bend without twist.
In the meantime, the LCD also includes a plurality of switching elements for applying voltages to the field-generating electrodes and a plurality of signal lines such as gate lines and data lines connected to the switching elements. The signal lines make capacitive coupling with other signal lines and the common electrode, which serves as a load exerted on the signal lines to yield signal delay as well as their own resistances. In particular, the coupling between the data lines and the common electrode drives liquid crystal molecules disposed therebetween to cause light leakage near the data lines, thereby deteriorating the light leakage. In order to prevent the light leakage, a black matrix may be wide to reduce the aperture ratio.